Load creation apparatus and method

ABSTRACT

A load creation apparatus is adapted to create a specified mass intended to be suspended such that a load bearing structure is able to bear the mass. The apparatus includes a liquid impervious container. The container is suspended from he load bearing apparatus by suspension means. The container is able to be filled with liquid to create the test mass. The mass of the container is obtained by means for determining the mass of liquid in the container from the density and volume of the liquid. A method is also provided for testing the ability of a load bearing structure to bear a specified test mass, created by such a load creation apparatus.

FIELD OF INVENTION

This invention relates to load creation apparatus, and to a method oftesting the ability of a load bearing structure to bear a test mass thatis created using such a load creation apparatus. The invention relatesparticularly, but not exclusively, to loads which are used for testingthe load bearing characteristics of hoists, cranes, davits, winches andother load bearing structures. The invention also relates to the testingof static load bearing structures, such as foundation piles, bridges,floors, jetties and wharves.

Specifically, the invention does not relate or extend to containers andapparatus in general that are not adapted or designed for load creationand testing purposes.

BACKGROUND

The ability of a load bearing structure to bear maximum loads willdecrease with its length of service, due to wear and tear of theapparatus. For this reason, it is necessary and sometimes mandatory thatload bearing apparatus, such as hoists, cranes, davits and winches betested periodically to verify that the apparatus are still capable offunctioning at the maximum load capacity. In addition, such tests may berequired when substantial alteration or repairs are made to theapparatus.

The tests require the load bearing structure or apparatus tosuccessfully bear a specified test load or, more precisely, a test mass.Typically, test masses are in the range of a few metric tonnes to morethan a few thousand metric tonnes and, in most cases, are in the rangeof 25% in excess of the safe working load of the load bearing structureor apparatus. Earlier test masses have been made of concrete or metal.Over a period of time, such test masses made of concrete can chip orcrack and may thus loose their original precision of mass due to wearand tear. Metal objects will tend to rust, and may in some cases sufferfrom metal fatigue or crack propagation. Furthermore, these tests areconducted only periodically. It is appreciated that between tests, thestorage of these solid test masses can create an inconvenient storageproblem. Furthermore, the problem is exacerbated when a range of testmasses, required for different apparatus, must be stored.

In response to the problems inherent in the use of solid test masses,the use of flexible liquid-filled bags as test masses has been proposedin United Kingdom Patent No. 2,047,414B (Tonnes Force Testing ServicesLimited) and United Kingdom Patent No. 2,072,351 (Water WeightsLimited). The bags used in these British patents consist of flexibleenvelopes that are filled typically with water in order to create thenecessary test mass. The liquid-filled bags resemble generallypear-shaped objects that are supported either singly or in combinationsto create the specified test mass. Since these flexible bags arecollapsible when empty, they solve the problem of storage that isinherent in the use of metal or concrete test masses. However, while oneset of problems is overcome, the use of water or liquid weightsintroduces a different set of problems that is inherent in the use oftemporary masses, namely the problem of ensuring that the bag is filledwith the correct amount of liquid to create a mass of the correct value.

This problem of filling the bag accurately with the correct amount ofliquid must be seen in the light of the fact that the standards ofweight testing often require the masses to be within relatively finetolerances. For example, reference is made to British Standard BS 7121Part 2: 1991 which is entitled “Code of practice for safe use of cranes.Part 2. Inspection, testing and examination”. According to BritishStandard BS 7121, the test mass should be of proven accuracy to within±1.0%.

Another factor that presents difficulties in creating a temporary masswithin the acceptable margins is that the density of a liquid varieswith composition and temperature. Consequently, changes in the liquiddensity affect the mass. A cubic meter of pure water at 40° C. weighsaround 7.7 kg less than another cubic meter of water at 3.98° C. Thedensity of pure water at 40° C. is around 992.3 kg m⁻³, whereas at 3.98°C. it is around 1000 kg m⁻³. The density of sea water taken from theopen sea may vary between approproximately 1020 and 1030 kg m⁻³. Whenexpressed as the amount of salt per kilogram of sea-water, in terms ofparts per thousand by weight (o/oo), the salinity of sea-water variestypically from 34 to 37 o/oo and has been found to be as low as 5 o/ooin the Finland and as much as 41 o/oo in the northern part of the RedSea. The difference of density in sea water is caused mainly by thevariation in temperature and salinity. Fresh water and sea water are themost common liquids used to fill the weight testing bags. Hence, if abag is filled consistently with the same amount of liquid, the vagariesof liquid density means that the bag may not necessarily contain thesame mass on each occasion. These variables mean that the amount ofliquid required to fill the bag is not constant, and must be ascertainedin the context of the ambient conditions. These factors explain why thetask of filling bags, with what can amount to thousands of liters ofliquid, is not simple task, especially when the amount of liquid mayhave to be within ±1.0% of a specified amount as required by certainmandatory standards.

The vagaries discussed above mean that it is often necessary to weighthe mass using a weighing device such as a load cell or dynamometer.Although weighing the mass, at the time of using the test mass, canensure that the vagaries of the amount of liquid and the prevailingdensity of the liquid are taken into account, the use of a weighingdevice, in turn, presents another set of problems. It is appreciatedthat the calibration (and indeed the maintenance of that calibration) ofweighing devices used for masses in the range of a few thousand tonnesis expansive and not straightforward. Furthermore, the precision of thecalibration is lost progressively over time, which means that theexpensive process of calibration must be repeated regularly. Forexample, in British Standard BS 7121, the weighing device or weighbridgeused to ascertain the value of the mass must, at the time of conductingthe test, have been calibrated and certified within the last twelvemonths.

In the field of weight testing, the weighing devices usually includeelectrical components and circuitry. The use of such electrical weighingdevices presents peculiar problems in applications where inflammablematerials are in close proximity. For example, when testing cranes thatare used in petroleum production facilities, it is necessary to ensurethat the electrical weighing devices are shielded, so that any sparksfrom the weighing device will not initiate ignition of the petroleumproducts in the vicinity.

Another type of load bearing structure which must be tested with a testload is found in the piles used as a foundation of buildings. A testmethod is defined in A.S.T.M. D 1143-8 (American Society for Testing andMaterials) which is entitled “Standard Test Method for Piles UnderStatic Axial Compressive Load.” After the foundation piles have beendriven into the ground, the piles must be subjected to a staticcompressive load to test whether each pile has adequate load bearingcapacity. The test loads are usually created by soil, rock, concrete,steel or water-filled tanks. These solid masses are usually solid, andare often in the form of large concrete blocks. Therefore, problemssimilar to the ones mentioned above in connection with solid test massesare experienced in transporting and positioning the large, solid masseson the test rig, and in storing the solid test masses when not in use.Furthermore, a weighing device in the form of a hydraulic jack isrequired to determine the actual test load, and this hydraulic jack mustbe regularly calibrated and certified. Other types of load bearingstructures that must be tested with compressive loads include bridges,floors, jetties and wharves.

An object of the present invention is to overcome or substantiallyameliorate at least some of the disadvantages of the prior art, and itis not intended that the invention in its broadest aspect mustnecessarily overcome all of the abovementioned problems in the priorart.

SUMMARY OF INVENTION

According to the present invention, there is provided a load creationapparatus operatively adapted to create a specified mass which issuitably large for load testing a load bearing structure, comprising:

a liquid impervious container;

means for filling the container with liquid to create the specified masstherein;

suspension means for suspending the container such that said loadbearing structure is able to bear said specified mass; and

wherein the container is provided with determination means fordetermining the mass of the liquid which forms the specified mass in thecontainer, the mass being determined from the density and volume of theliquid.

The determination means may be provided in the form of said containerbeing substantially shaped as a regular geometric shape at least atthose regions that are adjacent the liquid in the container such thatthe volume of liquid in said container is readily calculable.

The determination means may be provided in the form of said containerbeing provided with walls which, in use, are upright at least at thoseregions that are adjacent the liquid in the container.

Preferably, the walls, in use, are generally vertical at least at thoseregions that are adjacent any liquid in the container.

The determination means may be provided in the form of said containerbeing provided with a base that has a predetermined surface area.

The base may be orthogonal, and the base may be level.

The determination means may include a calibrated gauge which provides avisual indication of the level of liquid to which the container must befilled when the liquid has a particular density.

The visual indication may be adjustable in accordance with the densityof the liquid.

The liquid impervious container may be made of flexible material.

The means for filling may be in the form of an opening for saidcontainer.

The means for emptying the container may be in the form of liquiddischarge valve in the base of the container.

The suspension means may be in the form of a central strap which extendsgenerally through the center of gravity of said container when liquid isin the container.

The container may be divided into partitions by an internal web thatconnects internal surfaces of the container, said web functioning as astructural brace for the container when the container contains liquid.

Liquid may be able to flow from one partition to an adjoining partitionthrough vents located in the web.

Alternatively, the walls of the container may be provided with flatreinforcing components which enable the walls, in use, to remainupright.

Alternatively, or in addition to the reinforcing components, at leastsome of the walls of the container may be connected one to another withreinforcing struts, each of the struts functioning as a structural bracefor the container when the container contains liquid.

According to another aspect of the invention, there is provided anarrangement for creating a specified mass for testing a load bearingstructure comprising a plurality of load creation apparatus each ofwhich are suspended, wherein said plurality of apparatus are juxtaposedwith respect to one another.

The juxtaposed apparatus may be connectable by vents that enable atleast one of the apparatus in the arrangement to be filled with liquidreceived from at least one other of said plurality of apparatus.

The vents may be in the form of a flexible duct that is able tointerconnect adjacent apparatus.

The apparatus may be used for testing the ability of a load bearingstructure to bear a specified test mass.

The arrangement may be used for testing the ability of a load bearingstructure to bear a specified test mass.

According to a further aspect of the invention, there is provided amethod of testing the ability of a load bearing structure to bear asuitably large specified test mass, comprising the steps of:

using suspension means to suspend at least one load creation apparatussuch that the load bearing structure is able to bear a specified masscreated by said load creation apparatus, said apparatus comprising aliquid impervious container;

filling said container with liquid to create said specified masstherein; and

using determination means provided on said container to determine saidmass of the liquid which forms the specified mass in the container, themass being determined from the volume and density of the liquid.

The method may involve the step of ascertaining the volume and densityof the liquid and thereby determining the mass of the liquid therefrom.

Preferably, the determination means are provided in the form of saidcontainer being provided with walls which, in use, are upright at leastat those regions that are adjacent the liquid in the container and saidcontainer being provided with a base that has a predetermined surfacearea, and wherein said method involves the step of calculating thevolume of said liquid by multiplying the base surface area by the heightof said liquid in the container and determining the value of the mass ofthe liquid therefrom.

The method may involve the step of ascertaining the density of liquidand thereby determining the amount of liquid with which to fill thecontainer in order to produce the specified mass.

A plurality of said apparatus may be suspended in accordance with theabovementioned arrangement.

Liquid may be poured initially into one of said plurality of apparatus,and liquid from said one apparatus may flow to at least one other ofsaid plurality of apparatus.

Preferably, one of more of said other apparatus are provided each with avalve which prevents the liquid from escaping from the apparatus suchthat the liquid is constrained to flow to at least one other of saidapparatus until all the apparatus in the arrangement have beensubstantially filled to the required level.

The valve may be a float valve that is opened and closed by a floatablemechanism.

According to yet a further aspect of the invention, there is provided aload creation apparatus operatively adapted to create a specified masswhich is suitably large for load testing a load bearing structure,comprising:

a liquid impervious container;

means for filling the container with liquid to create said specifiedmass therein; and

suspension means for suspending the container such that said loadbearing structure is able to bear said specified mass;

wherein said container is provided with upright walls which are arrangedand operatively adapted to determine the volume of the liquid therein,so that the specified mass created by the liquid in the container isable to be determined by reference to the density of the liquid.

The apparatus may be used for testing the ability of a foundation pileto bear a specified test mass.

The arrangement may be used for testing the ability of a foundation pileto bear a specified test mass.

The load bearing structure may be a hoist, crane, davit, winch or othersimilar load bearing structure.

In the specification and claims, it is said that the test mass isintended to be suspended such that a “load bearing structure” is able tobear the test mass. The word “structure” is not intended to introduceany limitation on the type of structure, apparatus or machine that isable to be tested. For example, embodiments of the invention may be usedfor testing lifting machines such as hoists, cranes, davits and wincheswhere the load is suspended from the apparatus. Other embodiments of theinvention may be used to create a compressive load to be borne by loadbearing structures such as structural foundation piles. The inventionmay be used to test a wide range of load bearing device which must betested with a specified test mass.

In the specification, the word “filled” is used in the descriptive senseof adding liquid to the container. The word “filled” is not intended toimply that the container must necessarily be filled to the brim.

DRAWINGS

In order that the invention might be more fully understood, embodimentsof the invention will be described, by way of example only, withreference to the accompanying drawings, in which:

FIG. 1 shows a perspective view of an embodiment of a load creationapparatus;

FIG. 2 shows a cross-sectional view of the embodiment of the loadcreation apparatus in FIG. 1;

FIG. 3 is a plan view of the embodiment of FIGS. 1 and 2;

FIG. 4 is an under-side view of the embodiment of FIGS. 1, 2 and 3;

FIG. 4A is a perspective drawing of a further embodiment showing aninternal corner of a container having reinforcing strips attached to theinternal surfaces;

FIG. 4B shows a cross-sectional view of a modification of the embodimentin FIG. 4A in which the reinforcing strips are provided with reinforcingstruts to reinforce the surfaces of the container;

FIG. 5 illustrates another embodiment of the invention consisting of anarrangement of three load creation apparatus;

FIG. 6 illustrates a further embodiment of the invention consisting ofan arrangement of two load creation apparatus positioned one above theother;

FIG. 7 illustrates a more complex embodiment of the invention consistingof an arrangement of twenty load creation apparatus arranged in twotiers;

FIG. 8 shows an embodiment of a calibrated density gauge positionedadjacent a slit;

FIG. 9 shows a plate that is usable with the density gauge of FIG. 8;

FIG. 9A shows the plate of FIG. 9 slideably and fastenably mounted inthe slot shown in FIG. 8;

FIG. 10 illustrates a modification of the plate of FIG. 9, a differencebeing that the plate in FIG. 10 is provided with a pivoting float valvethat guards the opening at the upper end of the plate;

FIG. 11 illustrates an embodiment of a vent that is usable forconnecting one load creation apparatus to another;

FIG. 12 illustrates a connection between ducts of adjacent containers;

FIG. 13 illustrates another embodiment of an alternate connectionbetween ducts of adjacent containers;

FIG. 14 illustrates an embodiment of a load creating apparatus that issuspended by a rig, such that a structural foundation pile is able tobear the mass created by the load bearing structure; and

FIG. 15 is a side view of an embodiment similar to that of FIG. 4,except that the embodiment in FIG. 15 uses two decks of containers.

In the embodiment and drawings, similar components are numbered with thesame numerals for the sake of simplifying the understanding of thedescription. For example, the containers are labeled in the each of theFigures with the same reference numeral “16”, and the plate in FIG. 9 isgiven the same number of “41” as in FIG. 10 although the two platesrelate to different modifications. Hence, the similarity in numbersshould not be taken to imply that the features in each embodiment neednecessarily be of identical design.

EMBODIMENTS

Referring to the drawings, FIG. 1 shows a perspective view of anembodiment of a load creation apparatus, which is generally indicated as15. The embodiment is shown in FIG. 2 from a side view, and in FIGS. 3and 4 from a plan and under-side view respectively.

The load creation apparatus 15 is provided with a liquid imperviouscontainer in the form of container 16. The container 16 is made of awoven polyester fiber coated with PVC that is blended with a specialresin, but may also be made from any suitable tough, liquid imperviousmaterial.

The liquid impervious container 16 is provided with means for fillingthe container with liquid. In the present embodiment, this is providedsimply as an open top for the container through which liquid is able tobe poured. Other alternatives may have the container provided with aclosed top with a restricted liquid inlet.

The liquid impervious container 16 is also provided with means foremptying the container which, in the embodiment, is in the form ofliquid discharge valve 30 located in the base of the container.

It is anticipated that fresh water and sea water will be the usual typeof liquids used to fill the apparatus and arrangements described anddefined herein, because these liquids are readily available from naturalsources and are cheap. However, other liquids may be used at thediscretion of the user.

When the container 16 is filled with a sufficient mass of liquid, theresulting mass is suitable for use as a test load that can be suspended,such that a load bearing structure under test (not shown) is able tobear the mass in the container 16. The load bearing structure or devicesmay be a hoist, crane, davit, winch, or other pulling or lifting machineor any such device that must be tested by suspending a specified load.These may also include static load bearing structures such as foundationpiles.

The apparatus 15 is also provided with suspension means for suspendingthe container 16 such that a load bearing structure (not shown) is ableto bear the mass in the container. The suspension means, in theembodiment, includes a central strap 31 which extends generally throughthe center of gravity of the container 16 when it contains liquid. InFIG. 2, the strap passes through a sleeve running through the center ofthe container 16. The bottom end of the strap is provided with anoversized eyelet 33 that prevents the central strap 31 from pullingthrough the sleeve. The eyelet 33 serves a further function of enablinganother container to be suspended beneath the present container 16.(Such an arrangement is illustrated in FIG. 6.) Referring to FIG. 4, areinforced PVC plate 34 is provided at the base of the container to actas a further reinforcement for the central strap 31, in order to anchorthe end of the strap to the base of the container. In FIG. 2, the topend of the strap is provided with an attachment means in the form of ahook 29. The hook is formed with a supporting boss 28. The underside ofthe boss 28 is provided with an eyelet. The hook 29 is detachablyfastened to the central strap 31 by means of a shackle 32 that passesthrough the eyelet that is on the underside of the boss 28. The centralstrap 31 carries the bulk of the mass in the container 16. The supportmeans for the container 16 may also include secondary supports 25 thatextend from the hook 29 to the peripheral edges of the container 16.Thus, the entire apparatus 15 is able to be suspended from the loadbearing structure using the hook 29 to suspend the container, aided bythe central strap 31 and the secondary supports 25, such that the loadbearing structure is able to bear the mass of the apparatus 15.

In FIG. 1, the secondary supports 25 are attached to the container 16 bybeing connected to external straps 22 that are evenly spaced around theupper rim and sides of the container. The ends of the external straps 22are provided with shackles 24 to facilitate attachment of the externalstraps 22 to the secondary supports 25. The external straps 22 extenddown the side of the container and, as seen in FIG. 4, the externalstraps 22 surround the underside of the container and undergrid thecontainer 16. The container is effectively cradled in a web of externalstraps 22. In FIGS. 1 and 4, the external straps 22 pass through sleeves23 located on the side faces and on the under-surfaces of the container.The sleeves 23 hold the external straps 22 in place. On theunder-surface of the container as seen in FIG. 4, additionalstrengthening straps 35 are used to connect the web of external straps22 to the reinforced PVC plate 34. The reinforcing plate 34 is thusjoined to both of the external straps 22 and the central strap 31. Theplate 34 therefore acts as a connection between the central strap 31 andexternal straps 22. The internal and external straps are thus able toco-operate to support the mass in the container.

If, due to the size of container, there is found to be a tendency forthe secondary supports a deform the defined shape of the container bypulling the edge margins of the container towards the central axis ofthe container, then in order to counter-act this tendency, the edgemargins or rim of the container may be provided with some form ofstructural reinforcement. The reinforcement may be in the form of strutsthat brace the rim of the container in its intended shape. Furthermore,the face of the container may also be provided with reinforcing platesto enable the container to maintain its overall defined shape.

The central strap 31 and the secondary supports 25 are made of webbingmaterial or other suitable weight-bearing material. For extremely heavytest loads, the strap and the secondary supports may be reinforced withor made entirely of wire, or other suitable strong material.

Determination Means

An important feature of the present invention is that the container ofeach load creation apparatus is provided with determination means fordetermining the mass of any liquid in the container from the density andvolume of the liquid.

The invention relies on the fact that the mass of liquid is able to bedetermined from the volume and density of the liquid. The relevantequation is:

Liquid Mass (kg)=Liquid Volume (m³)×Liquid Density (kg m⁻³)

The mass is a constant and is fixed by virtue of the size of the loadspecified in the load test. The figure would probably be specified bythe manufacturer of the load bearing structure or by a certificationauthority. When the density of the liquid is measured, the aboveequation shows why the volume of liquid is inversely proportional to theliquid density. In other words, if the density and volume are known,then the mass of the liquid is able to be determined, without the needfor a weighing device or apparatus. This is the basis of how the presentembodiment is able to avoid the use of a weighing device for determiningthe mass of the liquid.

The user is able to ascertain the density of the liquid using ahydrometer. Common liquids, drawn from large reservoirs such as the seaor rivers, take a long time to change temperature in response to changesin ambient temperature. Once the liquid density has been measured, it isfound that the density reading is generally constant for a period oftime usually sufficient for the load test to be performed.

In the present embodiment, the user makes use of the determination meansto ascertain the required level of liquid with which the container mustbe filled. However, other embodiments may use other forms ofdetermination means that are designed to automatically control therequired amount of liquid.

Calculating the Mass by Determining the Volume and Density

In the embodiment shown in FIGS. 1 to 4, the means for determining themass of liquid in the container is present in the form of the container16 being substantially shaped as a regular geometric shape, at least atthose regions that are adjacent the liquid in the container such thatthe volume of liquid in the container is readily calculable. Hence, theembodiments of the invention can include containers shaped in anyregular geometric shape, so long as it is possible to readily performaccurate calculations to ascertain the volume.

Upright Walls

However, in the most convenient embodiments, the container 16 isprovided with walls which, in use, are upright at least at those regionsthat are adjacent the liquid in the container. When the container ismade of flexible material, only those portions of the container that arefilled with liquid would normally take on the final shape. Withoutliquid in the container, the upper portions of the container may sagslightly, but this is not critical provided that these portions doconform to the final defined shape when water is filled to up thoselevels.

The upright walls enable the volume of the liquid to be ascertainedsimply by multiplying the surface area of the base by the height of theliquid in the container. Accuracy is ensured when the walls aregenerally vertical at least at those regions that are adjacent anyliquid in the container. Strict compliance with 90° uprightness,although desirable, is not strictly required, provided that the amountof divergence does not cause the mass of liquid to vary outside theprescribed limits. For example, in the British Standard BS 7121, themass must be ±1.0%, and the degree of the measurement and arrangement ofthe walls of the container 16 must be such as to ensure that thenecessary precision is attainable.

The calculation is more readily performed if the base has a known area,and if the base is kept generally level during use. The invention in itsbroadest aspect does not require the base to be orthogonal, since it issufficient for the base surface area to simply be known so that it canbe multiplied by the height. Hence, the shape of the base may beorthogonal, square, rectangular, circular or any other shape. However,it is preferred that when using more than one such container in anarrangement, having an orthogonal-shaped base means that it is easier toarrange the containers closely side by side. (This feature will bediscussed below.) It is preferred, however, that the base is squarebecause it retains the benefit of having an orthogonal shape, while alsoensuring that the mass of liquid in the container will be evenlydistributed about the centre of gravity, as compared to moreelongated-shaped bases.

Hence, it is apparent that the use of upright walls in the presentembodiment in FIGS. 1 to 4 is a feature that confers an advantage on theapparatus. The advantage of having upright walls is that the volume ofthe liquid may be calculated readily by simply multiplying the base areaby the height of the liquid contained in the upright container. Furtherembodiments of the upright walls will be discussed in the context ofarrangements consisting of a plurality of containers.

It is appreciated that in the amorphous pear-shaped bags found in thetwo abovementioned prior art United Kingdom patents, it would bedifficult to calculate the height of liquid. The natural pear-shape ofearlier weight test bags was considered acceptable and not modifiedbecause, in the prior art, the shape was not considered to be a factorthat influenced the test procedure. In the prior art, where the mass isdetermined by a calibrated weighing device, the sole function of thebags was to contain the liquid. The shape of the bag was not consideredto have a bearing on the test result. Hence, the bags in the prior artwere made of flexible material and allowed to accommodate the liquid byfinding their own natural shape without any restrictions on the definedshape of the bag.

In use of the present embodiment, the load creation apparatus 15 in FIG.1 is suspended in such a manner that a load bearing structure (notshown), such as a crane for example, is able to bear the created load.The container 16 is the load creation apparatus 15 is filled withliquid. The density of the liquid is ascertained with a hydrometer, andthen the volume of liquid (and hence the height of liquid) required toproduce the mass specified for a test is ascertained. The container isfilled with liquid up to the height required to produce the specifiedmass. Thus, the specified mass is achieved accurately, without the needof a weighing device. This type of apparatus and this method are thusfree of the potential problems associated with weighing devices whichtend to lose accuracy and/or precision over a period of time.

The walls or panels of the container 16 are made of flexible materials,but the container, when filled with liquid, is not flexible in the sensethat the container does not permit the liquid to find its own shape. Theshape of the container 16 is achieved intentionally by providing thecontainer with flat sheet-like orthogonal walls. However, in practice,having merely four upright walls and a flat base is sufficient only forcontaining very small masses of liquid. For larger masses of liquid, theliquid would cause the walls of a simple open topped container to bulgeoutwards under the force of the liquid attempting to find its own shape.Since the shape of the container 16, in the present embodiment, isimportant to the working of the apparatus, the container 16 is dividedinto partitions by an internal web 18 that connects internal surfaces ofthe container. The web counter-acts the tendency of the walls to bulgeoutwardly under the influence of the water pressure. The web thereforefunctions as a structural brace for the container when it containsliquid. As shown in FIG. 1, there may be one or more of such webs. Thewebs may intersect. Liquid is able to flow from one partition to anadjoining partition through vents located in the web. The webs providesufficient bracing to enable the container to retain its shapeadequately when the container is filled substantially with liquid. Whencreating extremely large masses, the flexible faces of the container 16may be further reinforced with sheets of plates made of rigid materialsuch as PVC.

While the use of internal webs 18, mentioned above, provides adequatestructural rigidity for the container, other embodiments may usealternate forms of structural reinforcements that may cost less tomanufacture. Accordingly, instead of having the container divided intopartitions through the use of reinforcing webs 18, a further embodimentshown in FIG. 4A uses flat reinforcing components which enable thewalls, in use, to remain upright. The reinforcing components are in theform of reinforcing strips 70 which reinforce the faces of the container16. The reinforcing strips 70 are attached or fastened to internal facesof the container, as shown in FIG. 4A. However, the reinforcingcomponents may also be attached to external faces of the container.These reinforcing strips 70 contribute adequate structural reinforcementto the container 15. The strips are made of a suitably stiff material orwebbing, such as those that contribute a high degree of stiffness,similar to those used in conveyor and pulley belts. The reinforcingstrips may be flat, as illustrated in FIG. 4A, or the reinforcement maybe in the form of stiff rods (not shown). The reinforcing components mayalso be in the form of flat stiff panels that are attached to the sidesof the container. Other suitable materials are PVC, polyester orfibreglass. When the container is filled with liquid, the reinforcingstrips 70 provide stiffness to the faces of the container which enablesthe container to maintain the lateral faces in an upright disposition.

In a further embodiment shown in FIG. 4B, as an alternative to, or inaddition to the reinforcing strips 70, faces of the container areconnected with reinforcing struts 71 that are used to brace the sides ofthe container by linking surfaces of the container one to another. Thestruts 71 are detachable. The reinforcing struts 71 can be made of solidor flexible material. Flexible struts are acceptable since these areable to provide structural reinforcement when the strut is in tension.The struts 71 may be in the form of strips or may be in the form ofsolid components. The surfaces of the container are provided withshackles 72 that are used to connect the reinforcing struts 71 to theinner surfaces of the container. It is possible for these struts 71 toact as an alternative to using the reinforcing internal webs 18. Whenthe container is filled with water, the struts 71 are placed in tensionto hold the lateral faces of the container in the necessary uprightdisposition.

Calculating the Mass by Determining the Density Alone

The “means for determining the mass of the liquid” of the load testapparatus of FIG. 1 is provided with a further enhancement which isbased on the following equations used for calculating mass:

Liquid Mass (kg)=Liquid Volume (m³)×Liquid Density (kg m⁻³)

Liquid mass (kg)=Container base area (m²)×Liquid height (m)×Liquiddensity (kg m⁻³)

When the above equations is applied to the context of the presentembodiment, the following are constant: liquid mass, liquid density andcontainer base area. (The mass is specified by the test to be conducted.The density is ascertained from ambient conditions, and the base area isa fixed value.) Consequently, the only variable in the equation is theheight of the liquid in the container. The height of liquid is inverselyproportional to the density of the liquid.

Based on this principle, the load creation apparatus 15 is provided witha calibrated gauge shown in FIG. 8. The calibrated gauge is in the formof a liquid density meter 20. The density meter 20 provides a visualindication of the level of liquid to which the container must be filled,when the liquid is at a particular density. The meter 20 is adjustableto take into account variations in the density of the liquid arisingfrom changes in ambient conditions.

In the embodiment of FIG. 1, calibrated gauges are provided on all foursides of the container 16. Essentially, each meter 20 provides a scale,in this case, ranging from liquid densities of 0.990 g/cm³ to 1.040g/cm³, which is a typical range of densities of fresh water and seawater. The scale provides an indication of the height of liquid to whichthe container 16 must be filled in order to achieve a specified mass.For example, a container designed to create a ten tonne mass would havea liquid density meter 20 that would indicate the correct amount ofliquid necessary to achieve a mass of ten tonnes. This meter would beadjustable so that the user would know how much the vary the height ofthe liquid, depending on the prevailing liquid density, in order toachieve a mass of ten tonnes. The above equation teaches that the lowerthe density of the liquid, the larger amount of liquid that required tobe poured into the container 16, and vice versa.

In a simple embodiment, the calibrated gauge is simply a scale that hasbeen positioned accurately on the container, so that for each densityvalue, the scale indicates the height of liquid, corresponding to thatdensity, that is required to achieve the specified mass.

A further embodiment of a calibrated gauge is shown in FIGS. 8 and 9. Inthis embodiment, a calibrated density scale 40, ranging from liquiddensities of 0.990 g/cm³ to 1.040 g/cm³, is located on the side marginof an elongated slit 39. Liquid in the container is able to exit thecontainer through the slit 39. A pair of grooves 42 is provided oneither side of the slit 39. The grooves together form a slot on which aplate 41 is slidably mounted, as seen in FIG. 9A. The edge margins ofthe plate 41 are provided with a resilient coating, perhaps in the formof a rubber, polymer foam or any such resilient material that canenhance the liquid-tight seal that is preferably formed between theplate 41 and the grooves 42. The plate 41 functions in a similar mannerto a sluice valve that is slideable up and down in the slot. Thus, theliquid in the container 16 is only able to exit through the slit 39after the liquid reaches the level of the top end of the plate 41,marked A—A in the drawing. Thus, the level of liquid in the container 16is controllable by sliding the plate 41 up and down between the grooves42. The positioning of the plate in the grooves is determined by thedensity scale 40. In FIG. 9A, the plate is positioned to set therequired height of the liquid has a density of 1.015 g/cm³. The plate isable to set the upper height of the liquid in the container, because anexcess liquid will flow out of the container once the liquid reaches theheight A—A of the plate. Hence, the gauge in FIGS. 8, 9 and 9A acts as asluice valve which is able to vary the level of liquid in the container16. In FIG. 9A, once the liquid reaches the level set by the upper endA—A of the plate, any excess liquid flows over the end of the plate andout of the container 16 through the slit 39. The plate is provided withholes 43 which are used in conjunction with some form of fasteningdevice such as screws to fix the plate to the slot in the requiredposition.

Since the testing of the load bearing structure is concerned essentiallywith testing whether the structure is able to bear a specified mass, itis appreciated that the weight of the container itself 16 and the weightof the shackles, web, straps etc., will also add to the total mass thatis borne by the structure. Therefore, when designing the calibratedgauge, it is preferred that the weight of the components be consideredas part of the overall equation, as follows:

Test mass (kg)=Liquid volume (m³)×Liquid density (kg m⁻³)+Apparatus mass(kg)

In further embodiments, an apparatus such as in FIG. 1 may be used tocreate a range of masses. To facilitate this, the calibrated gauge maybe designed to indicate the heights of liquids required for a range ofmasses. Alternatively, a set of different gauges may be provided for theuser to select the appropriate gauge, depending on the mass to becreated. Charts may also be provided for making such modifications ofmass.

Arrangement of Plurality of Containers

For very heavy test masses, two or more load creation apparatus are ableto be suspended and juxtaposed with respect to one another.

Containers are available in a variety of standard weights, each intendedto create a particular mass. A plurality of these containers can becombined to form the total mass required. When creating an arrangementof two or more containers, the overall stability of the arrangement mustbe considered. For example, in order to create a nine tonne load, anarrangement of a five tonne container, sandwiched between a pair of twotonne containers, would provide better stability than, say, anarrangement of a five and four tonne container. For example, FIG. 5illustrates an arrangement of three load creation apparatus that aresuspended from a beam 36. (The beam is suspended from a load bearingapparatus). The apparatus are juxtaposed with respect to one another.The containers 16B, on either side of the central container 16A, are ofequal capacity to ensure the stability of the overall arrangement.

As mentioned above, the upright walls of the container provide anadvantage of being able to readily determine the volume of liquid in thecontainer. In an arrangement consisting of a plurality of apparatus, theupright walls provide a further advantage in that the surfaces of eachcontainer are able to juxtaposed closely to an adjacent container. Thisis in contrast to the prior art. When the pear-shaped amorphous bags,disclosed earlier in the United Kingdom patents 2,047,414B and 2,072,351are used in arrangements of more than one bag, the pear-shaped bagscannot be juxtaposed as closely to one another as those containers ofembodiments of the present invention that have upright walls. Thus, thearrangements of the type shown in FIG. 5 tend to take up less space thanarrangements that use the earlier pear-shaped amorphous bags. Similarly,it is appreciated that the apparatus are able to be more closelyjuxtaposed when the base of the container of the apparatus areorthogonally-shaped, such as in the shape of a square or rectangle.

In arrangements that use a plurality of load creation apparatus, it is apreferred, but not essential, that the juxtaposed containers areconnectable by vents that enable at least one of the containers in thearrangement to be filled with liquid received from at least one of theother containers in the arrangement. Liquid flows from container tocontainer through the vents. The vents are in the form of flexible ducts47 that interconnect adjacent containers. An example of a vent is shownin FIG. 11.

FIG. 12 shows how two flexible ducts 47A, 47B from adjacent containers16A, 16B are able to be connected by a coupling 48 which comprises apair of rings, one ring on each of the ducts, such that the ducts areconnected when the pair of rings are forced together with a frictionfit. Other mechanisms may be contemplated to produce the connection ofthe ducts, for instance, catches or screw threaded ends may be used. Inan alternative embodiment, FIG. 13 shows how two flexible ducts from twoadjacent containers 16A, 16B are joined together when the adjacentcontainers are juxtaposed closely. In this embodiment, the duct 47A fromone container 16A is sheathed within the duct 47B of the other container16B in a male-female connection. The ends of the ducts are held togetherwith a coupling 48.

Interconnections of containers is best effected between containers thatare shaped orthogonally, because when orthogonally shaped containers areplaced side by side, the flat walls discourage the adjacent containersfrom rotating. In contrast, when the containers have rounded surfaces,the suspended bags may have a tendency to swivel, and this could placestress on the vents that inter-connect the containers. Thus, in thosearrangements that do not have the benefit of upright-walled container,the vents should be designed with sufficient slack, so that they do notbecome taut in the event that the containers rotate slightly.

The vents are designed to allow liquid to flow through the vents. In theembodiment in FIG. 11, the opening at level A—A is adjusted to the levelrequired in accordance with the density scale, as has been described inconnection with FIGS. 8 and 9. However, in the present embodiment ofFIG. 11, the opening is surrounded by a flexible duct 47. The flexibleduct is able to channel or direct the overflow liquid to anotherlocation where it is required to fill other of the containers, ratherthan letting the liquid overflow out of the full container. The exit ofliquid from the container is controlled by the height at which the slit39 is blocked by the slidable plate 41 of FIG. 11. Therefore, since theflexible vent is controlled to the opening in the plate 41, liquid isable to flow through the flexible duct 47, wherever the plate isslidably located along the grooves 42.

Thus, the vent may either be elongated in shape to encompass the entireslit 39, or may be removably attached at different points on thecalibrated density scale device 40 to match the positioning of theopening created by the plate 41.

The function of the vents is to provide an interconnection betweenapparatus 16 in the arrangement. It is assumed that the vents couldconnect adjoining containers, but it is conceivable that is the ventsare formed in lengths, such as hoses, the vents may connect containersin the arrangement that are not directly adjacent. An example is shownin FIG. 6 in which the upper and lower apparatus 16A, 16B are notdirectly adjacent.

Procedure For Filling Arrangements of Plurality of InterconnectedApparatus

In the prior art, when a number of bags are used together, it isbeneficial to fill the bags simultaneously, otherwise the overallarrangement of bags might become unstable if a few bags on one side ofthe arrangement gain mass more rapidly that other bags. The problem isthat to fill all the bags simultaneously, a number of hoses must be athand to fill all the bags simultaneously.

In contrast to the prior art, in the present invention, arrangements ofa plurality of containers are able to be interconnected. Liquid can flowbetween the containers. Filling of the containers in the arrangementmight start, for example, with filling just one container, preferablyone which is close to the center of gravity of the entire arrangement.Subsequently, liquid from this initially-filled apparatus flow to one ormore of the other apparatus. Since there are no apparatus in thearrangement that are cut off from the circulation of liquid in thearrangement, the liquid is able to find its own level throughout thearrangement, and eventually fill all the apparatus in the arrangement.This filling of all the containers is achieved by using only a singlehose or pump, rather than a number of hoses as was required in the priorart.

For example, in FIG. 5, liquid is first poured into the center container16A. The adjacent containers 16B on either side of the center container16A receive liquid that flow from the center container 16A. In FIG. 6,another example is shown where the upper apparatus 16A is filledinitially. Once the upper apparatus 16A is filled, liquid exits theupper container and flows down to the lower apparatus 16B suspendedbeneath. The containers 16A, 16B are interconnected by a lengthy vent inthe form of a long hose 37. The end portions of the hose 37 are securedto the respective apparatus by coupling or other suitable water-tightfastening mechanism.

It must be borne in mind that the test mass created by such structuresmust be accurate often to within ±1% of the specified mass. This isachievable, in the present embodiment, because each one of the apparatusin the overall arrangement is provided with a means for determining themass of liquid inside the container. In the simplest embodiments, thisis achievable by the user ensuring that each container is filled to thecorrect height necessary to create the specified mass. For example, ifthe embodiment in FIG. 5 is to be filled with water from a nearby river,the user would start by ascertaining the density of the river water.Next, the liquid density meter 20 on each container is adjusted toindicate the correct level of water required for each container. Thenthe containers are each filled to the correct level prescribed theliquid density meter 20 on the container. Thus, the total mass of thearrangement—being the combined mass of the individual apparatus—would beaccurately determined. In more refined embodiments, each apparatus maybe provided with one or more of the sluice valves illustrated in FIG. 8.When water reaches the level determined by the valve, excess watereither empties to the ground, or is directed through vents to another ofthe apparatus. Thus, the level of water in each apparatus in thearrangement is individually controlled by its own “determination means”.Since the mass of each individual apparatus is guaranteed to be accuratewhen filled to the level prescribed by the liquid density meter, thetotal mass of the overall arrangement is thereby ensured.

FIG. 7 shows a much more complex arrangement of a plurality ofapparatus. In these complex and large arrangements, there is aparticular benefit of interconnecting the containers, because it ensuresthat a large arrangement will be filled with liquid without becomingunstable during the filling process. It would be extremely dangerous forsuch a large mass of liquid, which might be several hundred or thousandtonnes, to suddenly become unstable.

In FIG. 7, one possible procedure would be to commence filling bypouring liquid into the center apparatus 16A of the upper tier. Liquidfrom these center apparatus 16A would flow equally to the adjoiningapparatus 16B, and eventually to the end apparatus 16C. Thus, the toptier of apparatus would be filled while maintaining overall stability ofthe arrangement. Subsequently, liquid from the end containers would bedirected down to the lower tier through vents in the form of elongatedhoses 37 found on either side of the overall arrangement. Next, theouter apparatus 16D of the lower tier would begin to fill, and so forthuntil the overall arrangement of a plurality of apparatus has beenfilled.

In embodiments that have a plurality of containers, a “determinationmeans” is used which is a modification of the sluice valve of FIGS. 8, 9and 9A. The modification is shown in FIG. 10. A slideable plate 41 inFIG. 10, which is also slideably mounted in the slot between grooves 42,is different in the sense that the upper end A—A of the plate is guardedby a float valve 45. The float valve 45 pivots about an axis shown asA—A in FIG. 10. The benefit of providing a closeable float valve will beexplained as follows, with reference to the filling sequence describedfor FIG. 7:

The containers in each apparatus are provided with calibrated slits 39on all four sides of the container walls through which liquid is able toexit the container. The slits 39 on adjacent containers would beconnected by a vent. However, those slits 39 that are located on a faceof the container that is not adjacent another container would, if leftopen, act as an opening through which liquid would escape from theoverall arrangement, rather than being directed to another container inthe arrangement. Therefore, in practice, float valves 45 are used toblock all except usually one of the externally-facing slits of theapparatus on the tier. Only one, or at least a very limited number, ofthe externally facing slits on the same tier are left open without theuse of a float valve. Preferably, this one, or limited number of openvalves, is located at a point where the liquid will reach at or close tothe end of the filling sequence. So, in the example of the fillingsequence of FIG. 7, all the containers will be provided with floatvalves, except for the container 16E on the lower tier, which is exposedto receive liquid only towards the end of the filling sequence. Thelevel of these opened slits are set using the previously describedcalibrated gauge of FIG. 9A. The location of the open slit or slits(i.e. those not controlled by a float valve) would tend to be as faraway from the point at which liquid is poured into the arrangement. Thisensures that by the time excess liquid begins to drain through the openslit or slits, the likelihood is that all or most of the containers inthe arrangement would have been filled. All the apparatus in the uppertier are filled in the sequence described above.

When liquid in each container reaches the level of the float valve 45,the float shuts off the slits that are located in the externally-facingslits. This would cause each container with a slit blocked by a floatvalve to temporarily over-fill, so that the excess liquid has to flowout of the container into an adjoining container through theinterconnecting vents. Since all the containers in the upper tier areinterconnected by vents, any excess liquid in any of the containers canultimately drain out from the limited number of fully opened valves.Since liquid flows downwards, the one or limited number of valves withopen slits should be placed at the lowermost apparatus, or the apparatusin the arrangement or tier to which the liquid is expected to reachlast. For example, in the filling sequence of FIG. 7 described above,the container 16E in the middle of the lower tier is provided a valvewith an open slit.

In summary, the use of float valves for all except a limited number ofthe externally facing slits ensures that all the containers in the tierare filled substantially before any liquid is allowed to overflow fromthe upper tier into the lower tier. As liquid drains out of the limitednumber of fully opened slits, the liquid level in the over-filledcontainers begins to fall. When the liquid level drops to the level A—Aof the float valve of FIG. 10, the float valve pivots open, and theliquid in each container stops draining out of the container. Thus,every container in the arrangement achieves the right level of liquidnecessary for it to create its required mass. This is achieved by usingonly one liquid source, and obviates the need for having a separate hosefor each container.

When a plurality of apparatus are interconnected, filling shouldcommence with the highest container in the arrangement, since water onlyflows downwards.

In summary, the use of the present embodiment is considered to be verystraightforward. To create a test mass, the required number of apparatusare suspended such that the load bearing structure is able to bear theapparatus. The apparatus are interconnected. The density of the liquidis ascertained, and the gauge for each container is set accordingly.Then a hose is used to fill one of the containers, and eventually allthe containers will be filled to the correct amount to accuratelyproduce the specified test mass.

When the test for the load bearing apparatus has been completed, theliquid is drained from the apparatus by opening the outlet valve 30. Thebag can be folded and stored for further use.

The fact that the present invention is able to create an accurate masswithout relying on a weighing device, means that the present inventionis able to be used in proximity to flammable materials without thedegree of danger that would be associated if an electrical weighingdevice were to be required.

With the present invention, the need for a weighing device is obtained.However, ironically perhaps, the accurate test masses created by thepresent invention can actually be used for calibrating such weighingdevices.

Compressive Load Testing

FIG. 14 illustrates an embodiment of a load creating apparatus that issuspended using a suspensions means, in such a manner that a foundationpile 50 is able to bear the load created by the apparatus. In thisembodiment, the suspension means is in the form of a rig 60.

The load creation apparatus 15 is suspended from the test rig 60 whichimparts the mass to the foundation pile 50. The containers 16 of theload creation apparatus 15 are suspended from the rig 60, and filledwith liquid to create the specified test mass required to test the pile.

FIG. 15 is a side view of a similar embodiment to that of FIG. 14 whichuses two decks of containers.

In some testing procedures, such as A.S.T.M. D 1143, the load must beadded in increments of 25%. For instance, the initial load is appliedfirst at 25% of the pile design load. Then the load is increased to 50%,then 75%, then 100% of the design load, each time the load is borne bythe structure for several hours to provide time to observe any settlingof the pile. Then, the load is decreased in similar increments.Embodiments of the load creation apparatus are ideally suited to addingand taking away precise percentages of the pile design load. Theincremental increase and decrease of the load would be more easilyaccomplished than in the case where the load is created by solid blocksof concrete.

In the embodiment of FIGS. 14 and 15, a compressive load is borne by theload bearing structure. In addition to foundation piles, other loadbearing structures that may be tested include bridges, wharf decks,jetties, and other static load bearing structures. Even surfaces such asfloors and decks may have a stipulated load bearing capacity, and thesestructures may also be tested using embodiments of the invention.

The embodiments have been described by way of example only, andmodifications are possible within the spirit and scope of the inventionas defined by the appended claims. The invention and appended claims,however, do not relate or extend to cover containers, apparatus ormethods in general that are not adapted or designed specifically forload creation purposes.

What is claimed is:
 1. A load creation apparatus adapted to create aspecified mass for testing a load bearing structure, comprising: aliquid impervious container having walls; reinforcement means forreinforcing the container having first and second pair of sidewalls,each of said first and second pairs of sidewalls having a first sidewallopposing a second sidewall for bracing said first sidewall against saidsecond sidewall in each of said first and second pair of sidewalls, thesidewalls being respectively adjacent the walls of the container; thecontainer having means for filling with liquid to create a mass;suspension means for suspending the container such that said loadbearing structure is able to bear said mass; and wherein the container aknown volume for determining the mass of any liquid in the containerfrom a density and a volume of the liquid.
 2. An apparatus according toclaim 1 wherein the container is substantially shaped as a regulargeometric shape at least at one region that is adjacent the liquid inthe container such that the known volume of liquid in said container isreadily calculatable.
 3. An apparatus according to claim 1 wherein thecontainer has walls which, in use, are upright at least at one regionthat is adjacent the liquid in the container.
 4. An apparatus accordingto claim 3 wherein said walls, in use, are generally vertical at theregion that is adjacent liquid in the container.
 5. An apparatusaccording to claim 1 wherein the container has a base that has apredetermined surface area.
 6. An apparatus according to claim 5 whereinsaid base is orthogonal.
 7. An apparatus according to claim 5 whereinsaid base is level.
 8. An apparatus according to claim 1 wherein saidcontainer includes a calibrated gauge which provides a visual indicationof a level of liquid to which the container must be filled when theliquid has a particularly density.
 9. An apparatus according to claim 8wherein said visual indication is adjustable in accordance with adensity of the liquid.
 10. An apparatus according to claim 1 wherein theliquid impervious container is made of flexible material.
 11. Anapparatus according to claim 1 wherein said means for filling comprisesan opening for said container.
 12. An apparatus according to claim 1further including a means for emptying the container comprising a liquiddischarge valve in a base of the container.
 13. An apparatus accordingto claim 1 wherein the suspension means comprises a central strap whichextends generally through a center of gravity of said container when aliquid is in the container.
 14. An apparatus according to claim 1wherein said container is divided into partitions by an internal webthat connect internal surfaces of the container, said web functioning asa structural brace for the container when the container contains liquid.15. An apparatus according to claim 14 wherein liquid is able to flowfrom one partition to an adjoining partition through a vent located inthe web.
 16. An apparatus according to claim 3, wherein the walls of thecontainer are provided with flat reinforcing components which enable thewalls, in use, to remain upright.
 17. An apparatus according to claim 3wherein at least one of the walls of the container are connected one toanother with reinforcing struts, each of the struts functioning as astructural brace for the container when the container contains liquids.18. Use of an apparatus according to claim 1 for testing the ability ofthe load bearing structure to bear a specified test mass.
 19. A methodof testing the ability of a load bearing structure to bear a specifiedtest mass, comprising the steps of: using suspension means to suspend atleast one load creation apparatus such that a load bearing structure isable to bear a mass created by said load creation apparatus, saidapparatus comprising a liquid impervious container having at least twopairs of opposing walls; filling said container with liquid to createsaid mass; bracing said at least two pairs of opposing walls to maintaina substantially constant volume within said container; and determiningsaid mass of the liquid from a volume and a density of the liquid.
 20. Amethod according to claim 19 wherein said method involves the step ofascertaining the volume and density of the liquid and therebydetermining the mass of the liquid therefrom.
 21. A method according toclaim 19 wherein said container has walls which, in use, are upright ata region that is adjacent the liquid in the container and said containerbeing provided with a base that has a predetermined surface area, andwherein said method involves the step of calculating the volume of saidliquid by multiplying the base surface area by a height of said liquidin the container and determining a value of the mass of the liquid therefrom.
 22. A method according to claim 19 wherein said method involvesthe step of ascertaining the density of liquid and thereby determiningan amount of liquid with which to fill the container in order to producethe specified mass.
 23. A method according to claim 19 wherein themethod further comprises pouring liquid initially into one of aplurality of apparatus, and wherein liquid from said one apparatus flowsto at least one other of said plurality of apparatus.
 24. A methodaccording to claim 23 wherein the method further comprises providingeach of one or more of said other apparatus with a valve which preventsthe liquid from escaping from the apparatus such that the liquid flow toat least an other of said apparatus until all the apparatus in thearrangement have been substantially filled to a required level.
 25. Amethod according to claim 24 wherein said valve is a float valve andwherein the method further comprises opening and closing the float valveby a floatable mechanism.
 26. A load creation apparatus adapted tocreate a specified mass for testing a load bearing structure,comprising: a liquid impervious container; the container having a meansfor filling with liquid to create a load; and suspension means forsuspending the container such that said load bearing structure is ableto bear said mass; said container having at least two pairs of opposingupright walls, and a reinforcing means for reinforcing the walls of thecontainer, the reinforcing means bracing each of said two pairs ofopposing upright walls to maintain a substantially constant volume. 27.A load creation apparatus according to claim 26, wherein said walls aregenerally vertical in a region adjacent a liquid in the container. 28.Use of an apparatus according to claim 1 for testing the ability of theload bearing structure to bear a specified test mass, the load bearingstructure being a foundation pile.
 29. A load creation apparatus adaptedto create a specified mass for testing a load bearing structure selectedfrom the group consisting of a hoist, a crane, a davit and a winch,comprising: a liquid impervious container having walls; reinforcementmeans for reinforcing the container having first and second pair ofsidewalls, each of said first and second pairs of sidewalls having afirst sidewall opposing a second sidewall for bracing said firstsidewall against said second sidewall in each of said first and secondpair of sidewalls, the sidewalls being respectively adjacent the wallsof the container; the container having means for filling with liquid tocreate a mass; suspension means for suspending the container such thatsaid load bearing structure is able to bear said mass; and wherein thecontainer has a known volume for determining the mass of any liquid inthe container from a density and a volume of the liquid.